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<html>
<head>


    <meta http-equiv="content-type" content="text/html; charset=utf-8">
<title>Calendar Control</title>

<style type="text/css">
/*margin and padding on body element
  can introduce errors in determining
  element position and are not recommended;
  we turn them off as a foundation for YUI
  CSS treatments. */
body {
	margin:0;
	padding:0;
}
</style>

<link rel="stylesheet" type="text/css" href="../../build/fonts/fonts-min.css" />
<link rel="stylesheet" type="text/css" href="../../build/calendar/assets/skins/sam/calendar.css" />
<script type="text/javascript" src="../../build/yahoo-dom-event/yahoo-dom-event.js"></script>
<script type="text/javascript" src="../../build/calendar/calendar-min.js"></script>
<script type="text/javascript" src="../../build/history/history-min.js"></script>

<!--there is no custom header content for this example-->

</head>

<body class="yui-skin-sam">


<h1>Calendar Control</h1>

<div class="exampleIntro">
	<p>
  This example demonstrates how to use the Browser History Manager
  to remember which months have been viewed with the calendar widget
  and dynamically update it when the user presses the browser's
  back/forward buttons.
</p>
			
</div>

<!--BEGIN SOURCE CODE FOR EXAMPLE =============================== -->

<style>

#yui-history-iframe {
  position:absolute;
  top:0; left:0;
  width:1px; height:1px; /* avoid scrollbars */
  visibility:hidden;
}

</style>

<!-- Static markup required by the browser history utility. Note that the
     iframe is only used on Internet Explorer. If this page is server
     generated (by a PHP script for example), it is a good idea to create
     the IFrame ONLY for Internet Explorer (use server side user agent sniffing) -->

<iframe id="yui-history-iframe" src="assets/blank.html"></iframe>
<input id="yui-history-field" type="hidden">

<!-- Static markup required for the calendar widget. -->
<div id="container">
  <div id="calendarContainer"></div>
</div>

<script>

(function () {

    // The initial month will be chosen in the following order:
    //
    // URL fragment identifier (it will be there if the user previously
    // bookmarked the application in a specific state)
    //
    //         or
    //
    // today's corresponding month (default)

    var today = new Date();
    var defaultCalendarState = (today.getMonth() + 1) + "_" + today.getFullYear();
    var bookmarkedCalendarState = YAHOO.util.History.getBookmarkedState("calendar");
    var initialCalendarState = bookmarkedCalendarState || defaultCalendarState;

    var calendar;

    // Register our calendar module. Module registration MUST
    // take place before calling YAHOO.util.History.initialize.
    YAHOO.util.History.register("calendar", initialCalendarState, function (state) {
        // This is called after calling YAHOO.util.History.navigate, or after the user
        // has trigerred the back/forward button. We cannot discrminate between
        // these two situations.

        // Show the right month according to the "state" parameter:
        calendar.cfg.setProperty("pagedate", state.replace("_", "/"));
        calendar.render();
    });

    function handleCalendarBeforeRender () {
        var calDate, newState, currentState;

        calDate = calendar.cfg.getProperty("pageDate");
        newState = (calDate.getMonth() + 1) + "_" + calDate.getFullYear();

        try {
            currentState = YAHOO.util.History.getCurrentState("calendar");
            // The following test is crucial. Otherwise, we end up circling forever.
            // Indeed, YAHOO.util.History.navigate will call the module onStateChange
            // callback, which will call createCalendar, which will call calendar.render(),
            // which will end up calling handleCalendarBeforeRender, and it keeps going
            // from here...
            if (newState !== currentState) {
                YAHOO.util.History.navigate("calendar", newState);
            }
        } catch (e) {
            calendar.cfg.setProperty("pagedate", newState.replace("_", "/"));
            calendar.render();
        }
    }

    function initCalendar (startDate) {
        // Instantiate the calendar control...
        calendar = new YAHOO.widget.Calendar("calendar", "calendarContainer", startDate);
        calendar.beforeRenderEvent.subscribe(handleCalendarBeforeRender, calendar, true);
        calendar.render();
    }

    // Use the Browser History Manager onReady method to instantiate the calendar widget.
    YAHOO.util.History.onReady(function () {
        var currentState;
        // This is the tricky part... The onLoad event is fired when the user
        // comes back to the page using the back button. In this case, the
        // actual month that needs to be loaded corresponds to the last month
        // visited before leaving the page, and not the initial month. This can
        // be retrieved using getCurrentState:
        currentState = YAHOO.util.History.getCurrentState("calendar");
        initCalendar({ pagedate: currentState.replace("_", "/") });
    });

    // Initialize the browser history management library.
    try {
        YAHOO.util.History.initialize("yui-history-field", "yui-history-iframe");
    } catch (e) {
        // The only exception that gets thrown here is when the browser is
        // not supported (Opera, or not A-grade) Degrade gracefully.
        initCalendar({ pagedate: initialCalendarState.replace("_", "/") });
    }

})();

</script>

<!--END SOURCE CODE FOR EXAMPLE =============================== -->

</body>
</html>
